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Technical Info - Magnet ABC
Anisotropic Magnets
In the production process, a preferential direction is applied to anisotropic magnets by using an external magnetic field. In a magnetizing process following later, the maximum magnetic values are obtained in this direction.
Energy Product (B x H)
Product of flux density B and field strength H in the second quadrant of the
demagnetizing- curve. The energy product has a maximum (BH)max between
the points Br and BHc. The maximum energy product may be defined as
maximum stored magnetic energy and serves as material constant when
assessing permanent magnetic components (see fig. 1).
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Demagnetizing Curve
Part of the hysterisis loop within the second quadrant of the coordinate
system (B respectively M positive, H negative). By measuring the
demagnetizing curve, the most important magnetic features are determined.
Field Strenght (magnetic) H
Signifies value and direction of a magnetic field and may be defined in
various ways. For example: The potential energy of a small permanent
magnet with magnetic moment m within the magnetic field H is provided by: | |
Flux (magnetic)
Product from flux density B x area F, interspersed by the magnetic field.
Unit: 1 Vs = 1 Weber (Wb). | |
Flux Density (magnetic) B
Describes the strength of the magnetic field as H does. Whereas, outside magnetizable matter, B and H differ only by a constant factor, B accounts for the influence of the magnetisation within such materials.
Unit: 1 Vs/m² = Wb/m² = 104 G = 1 T
Most common are the units
1 T = 104 G und 1 mT = 10 G
Gauss
Formerly common unit of the magnetic flux density.
Isotropic Magnets
Isotropic magnets may be magnetized in all directions with the identical
magnetic features.
Coercive Field Force Hc
There is distinction between the coercive field force BHc, the flux density, and the coercive field force IHc of the polarisation. The coercive field force BHc (in the case of the closed magnetic circle) is defined as demagnetized field strength required for the removal of the flux density B. The coercive field force IHc is the demagnetized field strength whereby the polarisation I becomes zero. Thus, by applying IHc, a body becomes non-magnetic. Practically speaking, all materials with high permeability are magnetic, mainly iron, nickel, cobalt, and their alloys.
All other materials are non-magnetic (brass, copper, wood, stone etc.).
Magnetic charateristics of sintered hard-ferrites
| Quality |
|
Br |
bHc |
IHc |
(BH)max |
Thickness |
T-max |
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Identity No. |
mT |
Oe |
KA/m |
Oe |
KA/m |
KJ/m3 |
MGOe |
g/cm3 |
°C |
| OXI 100 |
Y10 |
>200 |
>1570 |
>125 |
>2640 |
>210 |
>0,8 |
>6,5 |
4,5-5,1 |
250 |
| OXI 300 |
Y25 |
>360 |
>1700 |
>135 |
>1760 |
>140 |
>2,8 |
>22,5 |
4,5-5,2 |
250 |
| OXI 340 |
Y30 |
>370 |
>2200 |
>175 |
>2260 |
>180 |
>3,3 |
>26 |
4,5-5,3 |
250 |
| OXI 340H |
Y30BH |
>380 |
>2890 |
>230 |
>2950 |
>235 |
>3,4 |
>27 |
4,5-5,4 |
250 |
Magnetic charateristics of neodymium-iron-boron magnets (NdFeB)
| Quality |
Br |
bHc |
IHc |
(BH)max |
Density |
T-max |
|
T |
KOe |
KA/m |
KOe |
KA/m |
MGOe |
KJ/m3 |
g/cm3 |
°C |
| N35 |
>1170 |
>10500 |
>836 |
>12000 |
>955 |
>33 |
>263 |
7,5 |
80 |
| N42 |
>1300 |
>10500 |
>836 |
>12000 |
>955 |
>40 |
>318 |
7,5 |
80 |
| N45 |
>1330 |
>10500 |
>836 |
>12000 |
>955 |
>43 |
>342 |
7,5 |
80 |
| N35H |
>1170 |
>10800 |
>860 |
>17000 |
>1353 |
>33 |
>263 |
7,5 |
120 |
| N42H |
>1300 |
>10800 |
>860 |
>17000 |
>1353 |
>40 |
>318 |
7,5 |
120 |
| N35SH |
>1170 |
>10800 |
>860 |
>20000 |
>1592 |
>33 |
>263 |
7,5 |
150 |
| N35UH |
>1170 |
>10800 |
>860 |
>25000 |
>1990 |
>31 |
>247 |
7,5 |
180 |
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Magnetic charateristics of magnetic foils/ magnetic strips
| Quality | Identity No. | Br
mT | bHc
KA/m | IHc
KA/m | (BH)max
KJ/m3 | Density
g/cm3 | T-max
°C |
|---|
| PERMAFLEX® 424 | 4/24p | 163 | 110 | 240 | 4,5 | 3,5 | 70 | | PERMAFLEX® 518 | 5/18p | 164 | 103 | 177 | 4,7 | 3,5 | 70 | | PERMAFLEX® 928 | 9/28p | 220 | 170 | 280 | 9,0 | 3,5 | 70 | | PERMAFLEX® 1750 | 17/50p | 173 | 205 | 524 | 17,0 | 3,5 | 70 | | PERMAFLEX® 5012 | 5/12 | 172 | 135 | 120 | 5,0 | 3,5 | 70 | | PERMAFLEX® 5014 | 5/14 | 172 | 135 | 140 | 5,0 | 3,5 | 70 |
Type of Magnetization
Magnetizing
Process of aligning the elementary magnetic areas by an external magnetic field.
Maxwell
Former unit for the magnetic flux.
Oersted
Former unit for magnetic field strength.
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Quality Control
Our products are subject to a strict entry and exit control, carried out in accordance to ISO 9000 ff regulations.
Our company is certified to ISO 9001-2003.
Certificate Register No. 052966 QM.
Remanence Br
Remanence is the induction (flux density) remaining in a ferrous magnetic material after removal of the magnetizing field. The numerical value of the remanence applies as material constant for the case of the closed circle (H = 0) and is called true remanence (Br). In the opened magnetic circuit Br drops to the value of the apparent remanence Br.
Saturation Magnetizing
A magnetization, which can maximally be achieved by parallel alignment of all magnetic moments, is called saturation magnetization.
Sintered Magnet
Permanent magnet pressed from a mixture of magnetizable powders and hardened by heating in a vacuum.
Temperature Coefficient
Indicates the dependency of the magnetic material's characteristic data Br and BHc upon temperature. The temperature coefficients for Br, respectively BHc differ.
Tesla
Unit for the magnetic Flux.
1 Tesla (T)= 104 G = 1 Vs/m2
Weber
Unit for the magnetic Flux.
1 weber (Wb) = 1 Vs = 108 Maxwell
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